TAS-Q1 Status & what if exercise Etude [HL-LHC] TAS-Q1

Situation actuelle

HiLumi Scénario : Vacuum IP side TAS-Q1: bellows+double pump

Current HiLumi baseline Machine side IP side  Gate Valve  Angle valves (2)  VAX  BPM  Gate valve + Bellows + Quick flange connectors  BPM (inside Q1 cryostat)… grey position.  Doble pump  Bellows + Quick flange connectors

What if… TAS fixed mechanically to Q1?  Bellows  Doble pump + Quick flange connector

Concerns  Q1 – structure structural rigidity, support, alignment  Cantilevered weight. 3.2 ton (tas w.o cradle). (Distance to first Q1 support ~4.1 m. Reactions at supports increased 6 to 8 ton+ bending moment --  Angular movement of the front plate. Support would probably need to be displaced towards IP… ( max 0.8 m) If TAS, no space, no easy alignment, etc,etc.  Vibration modes.  Larger IP region

Gains  TAS always aligned.  Eliminate need of bellows between Q1  No need of TAS alignment system.  If Q1 goes to 22.7 m last 2 BPM’s in green position. Ideally, this could be combined with the elimination of the “new BPM” at IP side: relaxing requirements for alignment, the need of interventions and giving a valuable space in the IP region.

8 BPM Position For optimal use during operations, the location of the BPMs should be positioned at least ±60 cm away of the beam crossing points, defined every 3.74m from the IP the “blind areas” Having an BPM that works with collision optics would be important for HL-LHC operation and in particular for luminosity levelling Courtesy P. Fessia Courtesy P. Fessia

9 TAS-Q1 Layout proposal for HL-LHC operation A. Maintain the same location of Q1 (L*=23m) and include the Q1-BPM into the cryostat – Allows for fixed mechanical connection between the BPM and the magnet cold mass therefore improved alignment and position monitoring during operations – Mitigates the risk of vacuum leak from the warm BPM of today – We also investigated the option to move Q1 further away from the TAS by ~1m (L*=24m) but doesn’t seem to work penalty for luminosity (small ~5% loss), doesnt’ really solve the access problems, and as all IT magnets would have to move accordingly, puts almost all BPMs of the SS to “blind” positions baseline

Page: EDMS No.REV.VALIDITY 10 STUDY BPM POSITION The “blind areas” where shouldn’t be positioned the BPM are located each 3.74m from the IP In this points the beams are crossed so the measurement is not so precise. To avoid this areas we should keep an area of 60cm to each side of those points. SmarTeam: ST _02 BLIND AREAS GOOD AREAS IPIPIPIP

Page: EDMS No.REV.VALIDITY 11 C1.R5 C1.R5 “LAY-OUT MACHINE” BPMSQ

Page: EDMS No.REV.VALIDITY 12 C2.R 5 BPMSQTBPMSQ “LAY-OUT MACHINE”

Page: EDMS No.REV.VALIDITY 13 C3.R 5 BPMSQT “LAY-OUT MACHINE”

Page: EDMS No.REV.VALIDITY 14 C4.R 5 BPMSQ “LAY-OUT MACHINE” BPMSQ

Page: EDMS No.REV.VALIDITYCONCLUSION Position of the BPM respect to the “blind areas” Moving L*  ( BMP )= -334mm blind area would be avoided

Page: EDMS No.REV.VALIDITY LHC  HL-LHC TAXN Q1 - Flange LHC Sections HL-LHC ?

Page: EDMS No.REV.VALIDITY SITUATION CMS CAVERN - LHC START MAGNETIC LENGTH Q1 1300mm ACTUAL START POSITION IN LHC LHC

Page: EDMS No.REV.VALIDITY 24000mm IP 5 SITUATION CMS CAVERN - L*24m ACTUAL START POSITION IN LHC START MAGNETIC LENGTH Q1 1300mm LHC HL- LHC

Page: EDMS No.REV.VALIDITY 23000mm IP 5 SITUATION CMS CAVERN - L*23m ACTUAL START POSITION IN LHC START MAGNETIC LENGTH Q1 1300mm LHC HL- LHC

Page: EDMS No.REV.VALIDITY 22666mm IP 5 SITUATION CMS CAVERN - L*22.7m START MAGNETIC LENGTH Q1 ACTUAL START POSITION IN LHC 1300mm LHC HL- LHC

Page: EDMS No.REV.VALIDITY SITUATION ATLAS CAVERN - LHC ACTUAL START POSITION IN LHC 1300mm LHC

Page: EDMS No.REV.VALIDITY 24000mm IP 1 SITUATION ATLAS CAVERN - L*24m ACTUAL START POSITION IN LHC 1300mm START MAGNETIC LENGTH Q1 LHC HL- LHC

Page: EDMS No.REV.VALIDITY 23000mm IP 1 SITUATION ATLAS CAVERN - L*23m ACTUAL START POSITION IN LHC 1300mm START MAGNETIC LENGTH Q1 LHC HL- LHC

Page: EDMS No.REV.VALIDITY 22666mm IP 1 SITUATION ATLAS CAVERN - L*22.7m ACTUAL START POSITION IN LHC 1300mm START MAGNETIC LENGTH Q1 LHC HL- LHC

 Are the potential gains real? If yes… strong enough to justify work on it?